INDIANAPOLIS — Coach Chuck Pagano began giving out the links of a chain before the first game of the Indianapolis Colts’ season. It was before they had reason to think he was doing anything more than trying to make a metaphor real, to bind a team of youngsters and castoffs, a few remaining veterans and those imported to be part of what Pagano refused to call a rebuilding but instead labeled a renovation.

As he handed a link to each player, Pagano delivered his message.

“He said you could be the last one, you could be the first one, but don’t be the missing one,” defensive end Cory Redding said. “Everybody on that team, when new guys came in, they got a link. We needed everybody to stay strong.”

The players still have their links. Redding’s is on a chain. Safety Tom Zbikowski keeps his in his bag. Punter Pat McAfee’s is with his car keys. But on that late summer night, Pagano did not account for one link, the one he became a few weeks later: unseen, but strong enough to keep the team he had bound since spring workouts from failing when everything around it seemed to be falling apart.

The giant inflatable Colts player that welcomed Pagano back to work after his nearly three-month leave for leukemia treatment was gone from the team headquarters’ snow-covered lawn last week.

The only reminders of Pagano’s ordeal are a small Chuckstrong sign in a locker room, the tiny orange stickers with his initials on each players’ nameplate, the hair on his head that is slowly growing back and the streams of text messages he sent from the hospital, late at night or in the middle of games, advising his players to take shorter steps on a punt or cursing them for allowing so many rushing yards.

Pagano, coaching in absentia after his treatment began during the fourth week of the season, guided one of the most inspiring performances in an N.F.L. season; almost everyone but the Colts says they overachieved.

The Colts won seven games with second-half comebacks from a tie or deficit, and it seems fitting that their season will come full circle in Baltimore, where Pagano was the defensive coordinator last season and where the Colts will play the Ravens on Sunday in an A.F.C. wild-card game.

“Guys had talked about it from Day 1, when we all got together in the off-season, we laid out our goals and expectations,” Pagano said in an interview last week. “We said just because of all the turnover and change, this guy is gone, that guy’s gone, we weren’t going to let anything determine the outcome of our season and how we played the game. So sitting back and watching, starting with the Green Bay game, all they knew was 60 minutes, all you’ve got, one play at a time. Don’t look at the scoreboard, don’t judge, just play hard. And expect something really good to happen when you do that.”

In Week 5, the Packers game was the first of the Colts’ comeback victories and the first game that Pagano watched from a distance. That made him feel powerless, despite the dry-erase board with the depth chart hung in his hospital room, despite the iPad the team loaded with practice film.

Even before Pagano’s illness, the Colts were the longest shot in the league. Their wrenching separation from Peyton Manning last March, after a two-win season that cost Jim Caldwell and Bill Polian their jobs, dominated the headlines while their remaking of the roster flew under the radar. When the Colts take the field against the Ravens, only 17 players on the 53-man roster will have been with the team last season. (Eight additional players on injured reserve were with the Colts in 2011.)

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Deji Karim, who last month was working as a parking attendant, went 101 yards on a kickoff in Week 17 for the Colts.CreditAj Mast/Associated Press

Among the new players is Jerrell Freeman, one of the league’s most productive linebackers, who was General Manager Ryan Grigson’s first signee. Freeman is an alumnus of the University of Mary Hardin-Baylor, which was a Texas women’s college until 1971 and played its first football game in 1998, and the Canadian Football League. A more recent addition is kickoff returner Deji Karim, who was working a month ago as a hotel parking attendant in Oklahoma City. Twenty-eight Colts will be making their first playoff appearance, including 14 rookies or first-year players, and as many as five rookies could start on offense on Sunday.

It fell to the offensive coordinator, Bruce Arians, to hold them together during Pagano’s absence. Practice times and routines were not altered.

Pagano made a point of staying in touch with his players. Redding said he received this text at halftime of a game: “If you read this at halftime, set the freaking edge.” McAfee said he had so many conversations and exchanged so many texts with Pagano that he wondered: “Don’t you have something you should be doing? Shouldn’t you be beating leukemia right now?” Arians talked to Pagano almost every morning, then delivered Pagano’s message to the team. Redding said it was almost as if Pagano were using sign language with Arians as his interpreter.

“B. A. has been around football a long time,” quarterback Andrew Luck said. “He’s seen most everything and knows how to handle situations. I think he understood what Chuck’s message was so well, it seemed seamless to us that he could continue that message. It wasn’t an abrupt change. It sort of felt like Chuck was never gone, almost. It was interesting to see him on the sideline again — oh, my gosh, that is Coach. I guess it is back to the routine.”

Pagano would like that. He wants to stop talking about his illness: the diagnosis, the chemotherapy, the migraines and the night sweats. Reviewing it when he returned, before the final regular-season game, was emotionally exhausting. The pregame ceremony to welcome him back produced sustained applause from the Houston Texans and almost brought Pagano to tears. Now he is ready to get back to something closer to normal, to return to the thrilling mundanity of preparing for a playoff game.

In the rush to return to work, Pagano, whose plight had motivated the Colts, allowed himself to wonder if his presence might upset their balance. But for the Colts, it has become impossible to separate inspiration from maturation.

“I think camaraderie is something that is overlooked a lot,” McAfee said. “Chuck’s big thing at the start of the year was, ‘We’ve got to become a team, a family.’ It was like our dad getting sick, so we all had to rally together for something that was bigger than us. It really brought our team together, especially for a young team that doesn’t know much about each other.”

When his leukemia, a treatable form, was diagnosed, Pagano asked his doctor for the odds and the game plan for his care. When he got to work last Monday, Pagano said, his world was back to normal. His doctors cautioned him not to overdo it, but Pagano re-immersed himself immediately in the details of coaching, getting the update on the weather and the grass conditions for practice, then bounding around in the bitter cold to take it all in.

“It’s almost surreal,” Pagano said. “When you’re going through it, the days are long. Three months later, you sit back, and I’ve had time to reflect with my wife and family, and it’s almost like, ‘Did we actually just go through what we went through?’

“I said there was never a doubt I would beat this and be back with my team. I didn’t know when that would be, but I’d be back. I told them there was never a doubt in my mind ever since we got together that this team could accomplish anything they set their minds to accomplish. When you have a faith and belief in something and you come together the way this team has come together as a family, the sky’s the limit. There was never a doubt I would beat my illness, and never a doubt whether you were down one score, two scores, all the comebacks we had, never a doubt you guys could get it done.”

Pagano got it done, too. During the months he was sick, the chain did not break. He was not the missing link.

A version of this article appears in print on , Section SP, Page 2 of the New York edition with the headline: In an Emotional, Rebuilding Season, the Colts Never Broke. Order Reprints | Today’s Paper | Subscribe